Regional assessment of dry and wet deposition of reactive nitrogen in East Asia

Satomi Ban1,2, Kazuhide Matsuda1

1 Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, Japan,

2 Japan Environmental Sanitation Center, 11 10-6 Yotsuyakami-cho, Kawasaki 210-0828, Japan


In order to investigate the state of reactive nitrogen deposition in East Asia, we carried out a measurement-based assessment of nitrogen deposition on regional scale in cooperation with the Acid Deposition Monitoring Network in East Asia (EANET). We estimated the dry deposition amounts of HNO3 and NH3 in gas phase, and NO3 and NH4+ in aerosol phase by a modified inferential method using monthly mean inputs of meteorological data. Dry deposition amounts estimated by the modified inferential method well reproduce those estimated by using high time resolution inputs in the case of long-term total dry deposition (e.g. annual deposition). The total (dry and wet) nitrogen depositions at 20 sites in 7 countries in East Asia were in the range of 2.8 – 37 kg N ha-1 year-1, and high total nitrogen deposition amounts over 10 kg N ha-1 year-1 were found in wide areas of the region. The highest amount in each site classification (urban, rural, and remote) was found at Chinese sites. The ratios of dry deposition to total deposition were high in the inland areas due to the low precipitation. And the ratios of reduced nitrogen to total nitrogen deposition were relatively high in southern part of East Asia.

Regional nitrate deposition inferred from ground- and space-based measurements

Miaomiao CHENG1, Zheng GUO2, Fan MENG1

1 State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China,

2 Division of Remote Sensing Data Application, National Satellite Meteorological Centre, Beijing 100081, China


Spatial and temporal nitrate deposition fluxes were assessed using satellite data in the Yangtze River Delta (YRD) from 1996 to 2011. Our study reveals significant spatial variations of nitrate deposition. In general, the fluxes of total (dry plus wet) nitrate deposition was up to 22 kg N ha-1 yr-1 with large loading rates received in winter. Most high fluxes appeared over urban (38 kg N ha-1 yr-1) and cropland (30 kg N ha-1 yr-1) areas. During the study period (1996-2011), a significant increasing trend of nitrate deposition was observed with an annual increasing rate of 1.33 kg N ha-1 yr-1. The spatial patterns of estimated nitrate deposition also showed that there were much higher fluxes and annual increasing trend in the middle region of YRD, i.e., the metropolitan areas contained Shanghai-Nanjing-Hangzhou cities, than in other areas. Our results also reveal that dry nitrate deposition contributed more than 50% of the total nitrate deposition over all provinces and land covers except coastal sea (14%), which indicates the relative importance of dry deposition to the total nitrate deposition in YRD region. Our study suggests that it is necessary to consider both dry and wet deposition when evaluating the influences of nitrate deposition on environment and ecosystem health.

Nitrogen inputs by rainfall, throughfall and stemflow in Brazilian semiarid

R. L. Deusdará1 2, M. C. Forti1, L. S. Borma1, R. S. C. Menezes3, J. R. S. Lima4, and J. P. H. B. Ometto1, E. R. Sousa-Neto1, K. Ribeiro1

1 Centro de Ciência do Sistema Terrestre – CCST, sala 5, 3º andar,  Instituto Nacional de Pesquisas Espaciais – INPE, Avenida dos Astronautas, 1758, 12227-010, São José dos Campos, SP, Brasil,


3 Departamento de Energia Nuclear – DEN, Universidade Federal de Pernambuco – UFPE, Av. Prof. Luiz Freire, 1000, 50740-540, Recife-PE, Brasil

4 Universidade Federal Rural de Pernambuco – UFRPE, Avenida Bom Pastor, s/n, Garanhuns – PE, 55292-270, Brasil


The aim of this study was to quantify nitrogen inputs by the rainfall, throughfall and stemflow, assessing the canopy role in the nitrogen transfers between atmosphere and soil in a rural tropical semiarid region in the Brazilian Caatinga. Samples were collected during two wet seasons, one during an extremely dry year (2012) and one during a year with normal rainfall (2013). The ionic concentrations of N-NH4+, N-NO3, dissolved organic nitrogen (DON) and dissolved total nitrogen (DTN) was 0.04 and 0.15, 0.07 and 0.10, 0.49 and 0.48, 0.61 and 0.73 mg l-1 in the rainfall for 2012 and 2013, respectively. The canopy enrichment for DON were 3 times for both wet seasons and for DTN were 3 and 2 times in relation to rainfall values for 2012 and 2013, respectively. There were no differences in N-NO3 between rainfall and throughfall. The enrichment for stemflow were 31, 8, 15 and 17 times for N-NH4+, N-NO3, DON and DTN for the wet season for 2013, respectively. We report a low bulk nitrogen deposition during both wet seasons and an estimative of about 2.05 kg N ha-1 ano-1. We estimated slightly lower annual inputs than previous global estimates, likely due to the low rainfall depths that occurred during the studied years and the lack of measured data for South America. Our findings contribute to the knowledge of nitrogen deposition in the northeastern Brazil by providing information for this poorly studied tropical and semiarid ecosystem.

Atmospheric nitrogen deposition in a subtropical hydroelectric reservoir (Nam Theun II case study, Lao PDR)

Adon1, C. Galy-Lacaux2, D. Serça2, F. Guerin3, P. Guedant4, A. Vonghamsao4, W. Rode4.

1 Laboratoire de Physique de l’Atmosphère et de Mécanique des Fluides, Université Félix Houphouët-Boigny, Abidjan, Côte d’Ivoire, E-mail :

2 Laboratoire d’Aérologie, Université de Toulouse, CNRS, UPS, France

3 GET (Geosciences Environnement Toulouse), UMR 5563, Toulouse, France

4 Nam Theun 2 Power Company Limited (NTPC), Environment & Social Division – Water Quality and Biodiversity Dept. – Gnommalath Office, P.O. Box 5862, Vientiane, Lao PDR


This study presents an estimation of the atmospheric inorganic nitrogen deposition into the NT2 hydroelectric reservoir, in the subtropical region of the Lao PDR, based on a two-year monitoring (June 2010 to July 2012) including gas concentrations and precipitation. Dry deposition fluxes are calculated from monthly mean surface measurements of NH3, HNO3 and NO2 concentrations (passive samplers) together with simulated deposition velocities. Wet deposition fluxes are calculated from NH4+ and NO3 concentrations determined in single event rain samples (automated rain sampler). Annual rainfall depth was 2502 mm and 3162 mm in 2010 and 2011, respectively. The average nitrogen deposition flux is estimated at 1.26 kg N ha-1 yr-1 from dry processes and 5.01 kg N ha-1 yr-1 from wet ones, i.e., an average annual total nitrogen flux of 6.3 kg N ha-1 yr-1 deposited into the NT2 reservoir with 80% from wet deposition.

Human nitrogen fixation and greenhouse gas emissions: a global assessment

Wim de Vries1,2, Enzai Du3, Klaus Butterbach-Bahl4, Lena Schulte-Uebbing2, Frank Dentener5

1 Alterra Wageningen University and Research Centre, PO Box 47, 6700 AA Wageningen, the Netherlands,

2 Environmental Systems Analysis Group, Wageningen University, PO Box 47, 6700 AA Wageningen, the Netherlands.

3 State Key Laboratory of Earth Surface Processes and Resource Ecology, and College of Resources Science & Technology, Beijing Normal University, Xinjiekouwai Street 19#, Beijing, 100875, China.

4 Karlsruhe Institute of Technology, Institute for Meteorology and Climate Research (IMK-IFU), Kreuzeckbahnstrasse 19, 82467 Garmisch-Partenkirchen, Germany.

5 Joint Research Centre, Institute for Environment and Sustainability, Ispra, Italy.


The net impact of human nitrogen (N) fixation on climate (ignoring short-lived components) mainly depends on the magnitude of the warming effect of (direct and indirect) nitrous oxide (N2O) emissions and the cooling effect of N-induced carbon dioxide (CO2) uptake. N-induced CO2 uptake is caused by anthropogenic N deposition which increases net primary production (NPP) in N-limited ecosystems and thus CO2 sequestration. Nitrogen oxide (NOx) emissions, however, also induce tropospheric ozone (O3) formation, and elevated O3 concentrations reduce NPP and thus plant C sequestration. We estimated global-scale impacts of anthropogenic N fixation on net greenhouse gas emissions using recent data and modelling approaches with respect to N inputs to various ecosystems, N2O emissions in response to N inputs, and C exchange in responses to N inputs (C–N response) and O3 exposure (C–O3 response). The estimated impact of human N fixation is dominated by an increase in N2O emissions equal to 1.02 (0.89–1.15) Pg CO2-C equivalent (eq) yr-1. CO2 uptake due to N inputs to terrestrial and aquatic ecosystems corresponds to net emissions of -0.75 (-0.97 to -0.56) Pg CO2-Ceq yr-1, while the reduction in CO2 uptake by N-induced O3 exposure corresponds to net emissions of 0.14 (0.07–0.21) Pg CO2-Ceq yr-1. Overall, human N fixation causes an increase in net greenhouse gas emissions of 0.41 (-0.01–0.80) Pg CO2-Ceq yr-1. Even considering all uncertainties, it is likely that N inputs lead to a net increase in greenhouse gas emissions.

Ammonia deposition in the neighbourhood of an intensive cattle feedlot in Victoria, Australia

Jianlin Shen1, Deli Chen2, Mei Bai2, Jianlei Sun2, Trevor Coates2, Shu Kee Lam2, Yong Li1

1 Key Laboratory of Agro-Ecological Processes in Subtropical Regions, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China (E-mail:

2 Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Victoria 3010, Australia (Email:


We conducted the first study in Australia to measure ammonia (NH3) deposition within 1 km from a commercial beef feedlot in Victoria. NH3 concentrations and deposition fluxes decreased exponentially with distance away from the feedlot. The mean NH3 concentrations decreased from 419 µg N m-3 at 50 m to 36 µg N m-3 at 1 km, while the mean NH3 dry deposition fluxes decreased from 2.38 µg N m-2 s-1 at 50 m to 0.20 µg N m-2 s-1 at 1 km downwind from the feedlot. These results extrapolate to NH3 deposition of 53.9 tonne N yr-1 in the area within 1 km from the feedlot, accounting for 8% of the annual NH3-N emissions from the feedlot. This high NH3 deposition rate nearby the cattle feedlot had caused the increase of soil inorganic nitrogen content, especially for NO3 (from 33 mg N kg-1 at 1000 m from the feedlot to 124 mg N kg-1 at 50 m from the feedlot). Higher N content (4.0% to 5.7%) in the above-ground part of grassland species and high cover rate of single species (e.g. a cover rate of 31% to 42% at 50 to 200 m from the feedlot for Cymbonotus lawsonianus) were found in the grassland transect  to the southeast of the feedlot. Our results suggest that NH3 deposition is significant nitrogen (N) nutrient input for surrounding croplands and natural ecosystems.

Twelve years of nitrogen deposition gap? An EMEP4UK model analysis

Massimo Vieno1, Mark Sutton1, Mathew Heal2, Anthony Dore1, Rachel Beck1, David Fowler1, Rognvald Smith1, and Stefan Reis1

1 Natural Environment Research Council, Centre for Ecology & Hydrology, Penicuik, UK,

2 School of Chemistry, University of Edinburgh, Edinburgh, UK,


An analysis of 12 years of annual nitrogen and sulphur deposition over the UK was carried out comparing atmospheric chemistry transport model (ACTM) results with an observation-derived calculation (CBED). The two deposition estimates agree well for oxidised sulphur, whereas total oxidised nitrogen deposition was underestimated by the ACTM. Possible causes of this discrepancy are the uncertainties of emissions estimates and the simplification in the ACTM aerosols formation. The CBED deposition estimates are less sensitive to uncertainties in the emissions inventory dataset as the UK deposition values are derived from observed deposition and surface concentrations. However, CBED wet deposition may be over-estimated due to dry deposition to the surface of bulk collectors. The UK deposition estimates show a general decline over the 2000-2012 period investigated; for oxidised sulphur ~86 (ACTM) and ~97 (CBED) Gg S yr-1, for oxidised nitrogen ~29 (ACTM) and ~45 (CBED) Gg N yr-1, and for reduced nitrogen ~7 (ACTM) and ~5 (CBED) Gg N yr-1.

Trends of monitored nitrogen species at monitoring sites in North America

Leiming Zhang1, Irene Cheng1, Xiaohong Yao2

1 Air Quality Research Division, Environment and Climate Change Canada, Toronto (

2 Ocean University of China, Qingdao, China


Long-term (1983-2011) air concentrations and annual wet deposition of ammonium and nitrate at 30 Canadian sites were analyzed.  Long-term median atmospheric NH4+ and NO3 ranged from 0.1-1.7 and 0.03-2.0 µg/m3 among the sites, respectively.  Median annual wet deposition varied from 0.2-5.8 and 0.8-23.3 kg/ha for NH4+ and NO3, respectively.  Long-term decline in atmospheric NH4+ from 1994-2010 was observed, whereas atmospheric NO3 increased from 1991-2001 and then declined from 2001-2010.  Annual wet deposition of NO3 decreased at most sites by 0.07-1.0 kg/ha/a. Average gaseous HNO3 and particulate NO3wet scavenging contributions to nitrate wet deposition were 72±23% and 28±23%, respectively. Gaseous NH3 and particulate NH4+ contributed 30±19% and 70±19% to wet NH4+ deposition.

Interannual variabilities in atmospheric ammonia during the most recent seven to eleven years were investigated at fourteen sites across North America.  The long-term average of NH3 ranged from 0.8 to 2.6 ppb among the four urban and two rural/agriculture sites in Canada.  The annual average at these sites did not show any deceasing trend with largely decreasing anthropogenic NH3 emission.  An increasing trend was actually identified from 2003 to 2014 at one urban site.  In the U.S., average NH3 from 2008 to 2015 was 2.2-4.9 ppb at three rural/agriculture sites and was 0.3-0.5 ppb at four remote sites.  A stable trend at one and increasing trends at three rural/agricultural sites were identified.  Increasing trends at the four remote sites were also identified.  Changes in NH4+/NH3 partitioning and/or air-surface exchange process as a result of the decreased sulfur emission and increased ambient temperature were believed to be the causes of NH3 at some of the sites

Anthropogenic aerosol depositions of nitrogen and phosphorus reduces the sensitivity of oceanic productivity to warming

Feng Zhou1, Rong Wang1,2, Yves Balkanski2, Laurent Bopp2, Philippe Ciais2

1 Sino-France Institute of Earth Systems Science, Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, P.R. China, Email:

2 Laboratoire des Sciences du Climat et de l’Environnement, CEA CNRS UVSQ, 91191 Gif-sur-Yvette, France


Satellite data reveal a strong link between contemporary oceanic productivity and climate. Models suggest oceanic productivity is reduced in response to enhanced water stratification induced by warming, but do not include the effect of increasing anthropogenic aerosol depositions of nitrogen and phosphorus (AAD). We model the response of oceanic productivity and chlorophyll to AAD, supported by in situ nutrient and chlorophyll measurements. As a result, AAD reduces the sensitivity of oceanic productivity to sea-surface temperature from -15.2±1.8 to -13.3±1.6 Pg C y-1°C-1 in the stratified ocean during 1948-2007. The reduction over the North Atlantic, North Pacific and Indian oceans reaches 40, 24 and 25%, respectively. We hypothesize that future reduction of aerosol emissions in response to higher air-quality standards will accelerate the decline of oceanic productivity per unit warming.